The present invention relates generally to methods and apparatus for rendering a composition including one or more pieces of footage into a final movie format, and more particularly to methods and apparatus capable of generating diverse output formats.
Programmed computers can be used to edit and create movies. For example, a computer program product called After Effects, available from Adobe Systems Incorporated of Mountain View, Calif., is licensed for use on a variety of personal computers and provides its user the ability to edit and create movies by integrating and arranging pieces of footage. In such programs, the process of creating a movie typically occurs in two major stages: modeling and rendering.
Modeling is the process of creating the structure for a movie project, commonly called a "composition", by defining the arrangement and timing of imported footage. A composition is essentially a set of instructions that define the processing of footage pieces in space and time in the formation of a movie. Each composition typically includes the definition of one or more layers, which are placeholders for pieces of footage. Modeling includes the sub-processes of: importing footage into the layers in a composition, editing the footage, arranging or "compositing" the various pieces of footage into an integrated whole, and finally adding any animation or other effects to the layers.
Imported footage may be in the form of digitized video, pictures, animations, drawings, stills or photographs. Each piece of imported footage is assigned to a layer. Layer properties may be individually edited by a user to control precisely any property over time. Layer properties that may be edited include the layer position, scale, rotation or opacity; the audio level; and the mask shape. For example, in editing a layer, a user can trim footage associated with the layer either spatially or temporally, or change the point from which a layer rotates.
Compositing integrates or combines the footage of the respective layers by using geometry masks, transparency information and effects. As the layers of the composition are integrated, animation and other effects may also be applied to each layer.
To create the final output, such as a film or videotape ready for viewing, the composition must be rendered. The rendering process transforms the footage and instructions associated with each layer into finished frames. During the rendering process, corresponding pixels from each layer are composited on top of each other to create a final image, a frame at a time, in the output format requested by the user. The frames may then be written for either analog or digital storage on a recording device such as a video tape recorder, photographic film recorder or digital disk recorder. In this way a movie is produced.
Typical render settings (i.e., user- or system-selected settings controlling some aspect of the rendering process) include the enablement (or disablement) of effects, the adjustment of resolution or quality of the frames, and frame manipulation settings associated with the final output format for the movie file.